In the present study, a poly(Rhodamine B)/graphene oxide/multiwalled carbon nanotubes nanocomposite modified glass carbon electrode (PRhB/GO/MWCNTs/GCE) was developed for the simultaneous determination of 2,4,6-trichlorophenol (2,4,6-TCP) and pentachlorophenol (PCP). The PRhB/GO/MWCNTs film was extensively characterized by emission scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy and electrochemical impedance spectroscopy (EIS). The electrochemical behaviors of 2,4,6-TCP and PCP were investigated by cyclic voltammetry, linear sweep voltammetry and differential pulse voltammetry. Due to the synergistic effect, the PRhB/GO/MWCNTs/GCE significantly facilitated the simultaneous electro-oxidation of 2,4,6-TCP and PCP with peak potential difference of 160 mV and enhanced oxidation currents. Under optimum conditions, the oxidation current of 2,4,6-TCP was linear to its concentration in the ranges of 4.0 × 10 −9 to 1.0 × 10 −7 M and 1.0 × 10 −7 to 1.0 × 10 −4 M with the detection limit (S/N = 3) of 8.0 × 10 −10 M. And the linear concentration ranges for PCP were 2.0 × 10 −9 to 1.0 × 10 −7 M and 1.0 × 10 −7 to 9.0 × 10 −5 M with the detection limit of 5.0 × 10 −10 M. Moreover, the proposed PRhB/GO/MWCNTs/GCE was successfully applied to the simultaneous determination of 2,4,6-TCP and PCP in practical water samples. [ABSTRACT FROM AUTHOR]